But every fitness expert seems to have a different opinion about how best to tighten the abdominal muscles. The amount of conflicting information can make it confusing if you're new to training.

San Diego State University set out to address this problem by finally answering the frequently asked question, "What's the best way to train the core?" (Read the study here.)

The Study

A team led by Peter Francis, Ph.D., and Jennifer Davis, M.A., in SDSU's Biomechanics Lab, conducted the study. They recruited 30 women and men (20 to 45 years old). Each participant was reportedly in good health with an activity level ranging from occasional to daily exercise. The researchers asked participants to perform a variety of abdominal exercises at random while hooked up an EMG machine, which monitored their level of muscular activity as they worked each movement.

Using the collected data, the researchers were able to establish each exercise's average level of muscle activity. Based on these numbers, the ab exercises were then ranked from best to worst.

The Results

Every tested exercise proved to be relatively effective—but some were more effective than others.

It's best to choose based on your preferences and experience. No matter which exercises you choose, take the time to train and strengthen your abdominal muscles. Strong abdominal muscles can help with posture, alleviate lower back pain and contribute to your long-term health.